I still have 10.3 as well. Never got around to installing the regression update and now it’s gone, presumably because they accidentally pushed the public release instead of 10.2 beta and they’re scrambling to fix it. Haven’t driven today (I did last night when I first got it to try it out, and it was fine with no traffic), but it sounds like if you are going to drive you should disable FCW and be very careful using even just AP on the freeway. It sounds like something they did screwed up badly and people on AP on the freeway have reported getting emergency collision braking (ie the car SLAMS on the brakes while going 70+mph hard enough to trigger ABS), which is very very very dangerous. Might be best to drive manually until they resolve it.
edit - Maybe consider turning off AEB period until a new update comes out. Videos are circulating of cars with 10.3 getting FCWs and emergency braking for no reason (phantom braking essentially) while AP is OFF and the car is being driven manually. FYI, you have to turn AEB off every time you shift to drive, iirc, since it’s a basic Safety feature. This is close to a disaster situation for Tesla. This went out to former 100s and 99s, so a wider audience, and they apparently broke a fundamental safety feature with this update. If someone gets slammed into from behind because of a false AEB event, that would be a huge PR disaster for Tesla. They’re probably scrambling to figure it out right now.